SOLVED - No start, dash icons illuminated & numerous service messages

[Oh Kee Pah]

I've been dealing with this since last week now. Had the gauges go a bit whacky when driving and a few weird service messages.
When I got home and went to start again later, Tahoe wouldn't start.
I disconnected the battery and reconnected.
Now, the dash icons illuminate, there is no start to the vehicle, and I get several service messages.
Service Airbag, Suspension System, Trailer Brake System, Front Camera, Theft Deterrent System, Tire Monitor System, Park Assist System, Side Detection System

From my investigating, I'm showing 11.9-12V on battery and no DTCs from scan tool.
This is a snapshot of while I was driving last week and the fist time gauges "acted up."

I've got the following on the list to be checked into, trying to get a tow into the Chevy dealer today.
1) new battery needed?
2) negative cable harness
3) battery grounded properly near vehicle frame - corrosion?
4) new BCM
5) OBD2 bypass kit for MRC delete? Passive battery drain or other corruption to ECM/BCM? - phone call to Xineering techs; they say there should be no correlation between their OBD/SS MRC delete product and my current experiences. That there product has a RAF that will not allow parasitic drain from the battery.

Safe Travels in 2022!

 

[Oh Kee Pah]

UPDATE:

Towed successfully by AAA to local Chevy dealership last night. Took me and the driver about 2 hours to manually shift into Neutral and work together to winch up onto the tow ramp.
Pretty lucky to actually get it out I think, and thankfully no property damage - it was TIGHT! Literally centimeters away from top of garage door and garage frame...I ended up standing on a step ladder to "push" up the bottom of garage door for final clearance of top roof rails.

I almost found it humorous last night, standing in the freezing cold, as we winched up the Tahoe from the depths of my garage - I put a lot of effort into measurements and making sure garage entrance clearance wasn't an issue with my 4" lift. I never thought about having to tow the vehicle out of the garage!
I have to say, the driver did an amazing job and I was very impressed at the control he had over the rig, winch and ramp all at the same time, truly a learned skill.

Prior to pulling the Tahoe up on the truck, we had to figure out how to get into Neutral. This crazy electrical issue I'm experiencing has the startup system basically dead. We tried jumping the vehicle with the AAA equipment but the Tahoe wouldn't even attempt to start. I am not able to access service mode, and when I think I have, the service messages and illuminated dash icons just start up all over again. Truly frustrating. Anyways, with no power there was no shifting. We found online (not in the TYForum) our answer. Removing the rubber steering shift protective cover and accessing a small mechanical pin inside the steering column. Using a small screwdriver and 3 flashlights, we were able to manually shift the truck into Neutral. Success! It felt good and I was pretty upset that the Chevy service rep told me the driver would have no problems...yeah right!

Dropped off the kids with my wife's Audi this morning and ran down to the dealership to review the situation and a couple other small items while I'm there. Told the service rep to hop in and try to start it, he'll see all the problems. Well guess what, one try and the damn thing started right up. Very sluggish, but it started. I've spent hours messing with this thing and of course right there at the dealership it shows no signs of the electrical gremlins of the past week! I immediately pulled out the cell phone to show him video, that I'm not a complete liar. And as I'm pulling up the video on the phone, low and behold, the dash lights up. The gauges drop and show nothing and then the service messages started rolling...I felt true relief. Pretty sad when you're actually GLAD to see the problem happen.

ZERO initial "thoughts" from the dealership BTW.

More updates to follow as this progresses.

 

[OR VietVet]

Freakin' GREMLINS! Hate 'em with a passion! Thanks for the update and future updates.

WAG-ground problems or battery cables.....IMO.

 

[Oh Kee Pah]

SOLVED:
UPDATE (post Chevy dealer diagnostics & services)

Well, they tell me the problem is solved and so far that is the case. My gut tells me there is probably an underlying issue with my BCM, but we are not at that point yet in the diagnosis with Chevy technicians quite yet.

The result of my Tahoe not being able to start is due to electrical issues. The dealership told me that the vehicle had entered "crash mode," initiated with my failing rear side sensors, and running to the BCM, resulting in the experienced computer "crash."


Approx. 3 months ago I took the Tahoe into Chevy dealer with service message:
Service Side Detection System
They provided the following diagnosis:

As this repair only seemed to effect my side detection and I could easily dismiss the message, I decided to sit on the "problem" until I had the extra $1500 on hand to easily take care of this issue...

Fast forward three months to the past 2 weeks of crazy dash activities, normal battery and total loss of ability to start. I can't believe this is what Chevy dealer came up with:

After servicing, the Chevy service rep called it a "cascade electrical failure" triggered by the faulty rear sensor. I COULDN'T BELIEVE IT! I was lucky enough that the rear sensors were somehow covered under the extended warranty and then I had to pay for parts & labor on the faulty sensor harness/wiring.
As stated, all seems to be fine now. But deep down I'm afraid the BCM was damaged with the overloads and attempts to jump the vehicle over the past months. I may just end up asking Chevy for a quote on a new BCM install - just to put my mind at ease. Really don't want to be stranded back in the woods because the stupid computer decided it was done working!

While the Tahoe sat in the shop being diagnosed, I found the following 2 TYForum threads (not seen previously unfortunately) that describe very similar electrical issues I was facing and the Tahoe entering "crash mode."

Thread regarding: Side Detection System; known GM issue...
Thread regarding: No start, cluster lights crazy, engine won't Turn Off

Lesson learned: TAKE CARE OF "little" ELECTRICAL ISSUES BEFORE THEY BECOME A BIG DEAL!!!


Safe Travels!

 

[Joseph Garcia]

Thank you for posting the solution to your issue.

Our collective knowledge base is increased.

 

[STORMIN08]

very good to know, just had a similar issue...although mine was a failed battery...but i do get that same side detection notice (twice that i recall in the last year).

 

[JediCordo]

@Oh Kee Pah .... A year later, was this still the root cause? I have a 2015 that the dealership can't tell us what is wrong with it. We replaced the battery. Want to know if I should start by replacing these sensors before I start attacking the electronic modules.

 

[OR VietVet]

Welcome to the forum, @JediCordo

 

[Doubeleive]

@Oh Kee Pah .... A year later, was this still the root cause? I have a 2015 that the dealership can't tell us what is wrong with it. We replaced the battery. Want to know if I should start by replacing these sensors before I start attacking the electronic modules.

you can't base your issue on what some one else experienced in this scenario, it literally could be anything.
ALL I can add is "IF" you inspect your rear blind spot sensors "harness" and find corrosion then unplug them and see if the issue goes away.
otherwise the dealership needs to do there job.

 

[JediCordo]

How do you get the dealership to do their job? They are the ones who sent me home with it Friday saying it was fixed!!

 

[JediCordo]

Reading more instances through this site; inspection of the grounding system should be my next task.

 

[Oh Kee Pah]

The issue originally posted about has NOT reappeared since the problem was "fixed."

I would still suggest considering a new Negative Cable Harness Assembly. That's basically your connection between the battery and brains. I feel that can be a faulty part in our vehicles, worth checking out...

 

[JMiner]

The issue originally posted about has NOT reappeared since the problem was "fixed."

I would still suggest considering a new Negative Cable Harness Assembly. That's basically your connection between the battery and brains. I feel that can be a faulty part in our vehicles, worth checking out...

I have a 2015 Suburban LTZ & my gauges were going crazy, service abs, stabilitrack, 4X4, every light was on, was in “Limp mode” no power steering (Power Steering Reduced alert on dash) wouldnt shift or start on occasion (gear indicator light flashing and clicking in dash) mainly after going through excessive rain/puddles but also if hit any potholes & even sometimes randomly while driving. A few times i could park and let it sit for about 15 mins and it would be ok for a short while then do it all over again. After hours of diag at a shop (no bus communication) they replaced the EBCM (Electronic Brake Control Module) & it fixed everything. There was also a few warning lights afterwards that were on caused by a connector that needed to be cleaned. Now everything works fine now dealership list price on the part was like $800, around $200 for the reprogram & expect some potential brake lines if they dont come out easy.